What are weekends for? In the mergers and acquisitions game, they are usually meant for structuring megadeals.

That was the case with WPP Group's (NASDAQ:WPPGY) $1.3 billion bid for Grey Global Group (NASDAQ:GREY). Yes, in the ad business, getting customers is really about buying your competitors.

The deal anoints WPP Group as the worldwide leader in advertising, with the No. 2 position held by Omnicom Group (NYSE:OMC). The deal also brings WPP the marquee client, Procter & Gamble (NYSE:PG), as well as strong penetration in Europe.

The transaction creates a tangled web of customers. For example, WPP Group has clients such as Colgate-Palmolive (NYSE:CL) and Unilever (NYSE:UL). Might this rankle Procter & Gamble? Well, apparently, WPP Group sought approval from Procter & Gamble before pursuing the bid.

The deal should result in cost savings -- estimated to be at least $20 million for 2005. Moreover, the CEO of Grey will stay until at least 2006. Then again, he will have $300 million to play with because of the acquisition.

There were two other bidders for Grey: Havas SA and a combined bid from Hellman & Friedman and Kohlberg Kravis Roberts, both of which are private equity firms.

In the case of Havas, the failure to snag Grey could prove fatal. In the land of the advertising giants, Havas is a small player, which may mean it is the next company to be buyout bait.

Fool contributor Tom Taulli owns none of the shares mentioned in the article.